Slant drilling tools for oil wells

ABSTRACT

Drill string orienting apparatus for nonrotating drill strings equipped with down hole motors, the orienting apparatus preferably being located between the lower portion of the motor and the bit sub and having a laterally projecting portion engageable with the hole formation to bias the bit directionally. Also, orienting apparatus on the string above the down hole motor having a portion projecting laterally opposite to the projection of the first mentioned orienting means. Also, a modification wherein symmetrical stabilizing means is located adjacent the lower end of the motor and laterally disposed directional orienting means is located above the down hole motor in spaced relation to the stabilizing means.

United States Patent [72] Inventors Erskine P. Garrison Long Beach; John E. Tschirky, Manhattan Beach, Calif. [21] Appl. No. 735,414 [22] Filed June 7, 1968 [45] Patented Feb. 9, 1971 [73] Assignee Smith Industries International Inc. Whittier, Calif. a corporation of California [54] SLANT DRILLING TOOLS FOR OIL WELLS 5 Claims, 8 Drawing Figs.

[52] US. Cl 175/76, 175/323 [51] Int.Cl E21b 7/06 [50] Field of Search 175/73- [56] References Cited I UNITED STATES PATENTS 2,734,721 2/1956 Zublin 175/76 2,891,769 6/1959 Page et a1. 175/76 3,036,646 5/ 1962 Eckel et a1. 175/ 107 8 e l I :3 1 -i I 3,068,946 12/1962 Frisby et a1. 175/73 3,298,449 1/1967 Bachman et a1. l75/230X FOREIGN PATENTS 1,247,454 10/1960 France 175/73 1,273,706 9/1961 France 175/73 Primary Examiner-Emest R. Purser Assistant ExaminerRichard E. Favreau Attorney-Allan D. Mockabee ABSTRACT: Drill string orienting apparatus for nonrotating drill strings equipped with down hole motors, the orienting apparatus preferably being located between the lower portion of the motor and the bit sub and having a laterally projecting portion engageable with the hole formation to bias the bit directionally. Also, orienting apparatus on the string above the down hole motor having a portion projecting laterally opposite to the projection of the first mentioned orienting means. Also, a modification wherein symmetrical stabilizing means is located adjacent the lower end of the motor and laterally disposed directional orienting means is located above the down hole motor in spaced relation to the stabilizing means.

PATENIEU FEB 91911 snm P 2 EQSZ/Nf P.

INVENTORS, awe/501v JOHN E. rsc/wezi AVTOQNEV PATENTED FEB 9 I97! SHEET 2 UF 2 NTOI 2 JOHN E. rsc/v/ez firme/vev SLANT DRILLING TOOLS FOR OIL WELLS The invention relates generally to orienting means for drilling apparatus such as used in the drilling of oil and gas wells. At times it is desired to perform slant-drilling operations where the hole is deliberately drilled on a slant or curve. At other times it is desired to drill a vertical hole in formations which tend to cause deviation of the drill and drill string from the vertical. In either situation, it is desirousto provide means for engaging the wall of the formation at one side to bias the drill and lower part of the drill string laterally.

In some drilling apparatus the drill string does not rotate, the drill bit being rotated by a down hole motor located a short distance above the bit and having an internal rotor connected to the bit and actuated by drilling fluid under pressure which is forced down through the nonrotating string or by any other suitable means. In such apparatus orienting means has been provided above the down hole motor, the latter being of considerable length so that the orienting means makes lateral contact with the hole fonnation a considerable distance above the bit and desired deviation of the hole from the vertical is not only quite gradual, but maintenance of the drill bit and lower portion of the string at the desired angle from the vertical is difficult to control.

It is an object of the present invention to provide drill bit orienting means located close to the bit in a convenient manner so that angular deviation from the vertical is more readily accomplished and the direction of the bit more positively controlled.

Another object of the invention is to provide orienting means which can conveniently be mounted on the lower bearing housing of a down hole motor and immediately above the drill bit sub.

A further object of the invention is to provide means for effectively and conveniently indexing the orienting means rotationally so that biasing of the bit and lower portion of the drill string can be provided precisely in the lateral direction desired.

Still a further object is to provide orienting means adjacent to the lower end of the string and adjacent the bit in combination with additional orienting means spaced upwardly from the first mentioned orienting means, each having laterally projecting means disposed in opposite directions to more effec tively produce slant drilling, or conversely, to maintain the hole on a vertical axis in difficult formations where slanting of the hole is not desired.

Another object of the invention is to provide orienting means located considerably above the bit and stabilizing means located adjacent the bit in downwardly spaced relation to the orienting means in order to produce a minimum of lateral biasing of the drill string and bit while maintaining contr'ol of the bit against unwantedlateral movement, as well as to provide for slant drilling at a minimum angle.

The above and other objects will more fully appear from the following description in connection with the accompanying drawings:

FIG. I is a side elevational view of an embodiment of the in vention partially in section with the upper orienting shoes extended;

FIG. 2 is a view similar to FIG. 1 with the upper orienting shoes retracted;

FIG. 3 is an enlarged section taken approximately on the line 3-3 of FIG. 1;

FIG. 4 is a side elevational view partially in section of a modified form of construction;

FIG. 5 is a side elevational view partially in section of still another form of the invention;

FIG. 6 is an enlarged sectional view taken approximately on the line 6-6 of FIG. 4;

FIG. 7 is an enlarged sectional detail of a portion of an orienting unit with a hydraulically actuated laterally movable formation engaging element; I

FIG. 8 is a side elevational view of an orienting device embodying the structure of FIG. 7.

In FIGS. I and 2 there is shown a drill string generally indicated at 8. Customarily. this is made of sections of drill pipe and drill collars threadedly connected and extending from the surface to the bottom of the hole. A sleeve I6 forms part of the string and supports a plurality of shoes 18 which can be projected laterally relative to the sleeve 16 to engage the sidewall of the hole being drilled. The number of shoes is not critical and the projecting means is not shown because devices of this type are well known in the art.

Secured to the lower end of the sleeve 16 is a down hole motor 20 which can be driven hydraulically. electrically or in any other suitable manner. Preferably, it is a hydraulically driven pump which utilizes the pressurized drilling fluid which is pumped down the drill string to the bit and which is also used to project the shoes I8 laterally from the sleeve I6. It includes an outer housing 22, and an internal rotor or drive shaft, not shown, the housing 22 terminating in a lower bearing housing 24 which houses the bearing for the lower end of the internal rotor or drive shaft. Secured to the bottom of the motor bearing housing 24 is a bit sub 26 having a drill bit 28 mounted for rotation therein and suitably connected to the motor rotor or drive shaft for rotation therewith in a manner not illustrated but also well known in the art.

The bearing housing 24 is provided at its upper portion with external threads 30 and upon them is threaded the upper end of an orienting sleeve 32 having a pair of vertical radially directed orienting fins 34.

The orienting means comprising the sleeve 32 and fins 34 can be used on the drill string with or without the upper or additional orienting means 16. It will be noted that the orienting fins 34 encompass only a fraction of the circumference of the orienting sleeve 32 and that they extend laterally a distance greater than the lateral extent of the drill bit 28.

In FIG. I the portion of the drill string illustrated is shown bent or sprung slightly to the left of center. This occurs because of the weight of the string on the element thereon. With the lower portion of the string bowed or-bent to the left as shown, the tendency would be for the drill to work on a slant toward the right as viewed in that FIG. This would be overcome by the orienting fins 34 which are disposed to the right and the upper orienting shoes I8 which are projected laterally to the left.

When it is desired to slant the hole 36110 the left as viewed in FIG. 1 for example, the drill string is lowered into the hole with the orienting fins 34 directed generally to the right. Since the drill string, the orienting sleeve 32 and its orienting fins 34 do not rotate, the fins will maintain the same position at one side of the hole 36. Because of the lateral extent of the orienting fins 34 relative to that of the drill bit 28, contact of said fins 34 with the sidewall of the hole will tend to bias the drill bit 28 to the left, or in the lateral direction opposite to that of the projection of the fins 34. This will cause the hole to assume an angle or curve toward the left, as viewed in FIG. I, where slant drilling is desired. If the formation being drilled is such that there is a tendency to cause the drill bit to move at an angle to the vertical, and where a vertical hole is desired, the orienting means comprising the sleeve 32 and fins 34 can also be utilized. With the orienting means in the position shown in FIG. I, the formation would be such as to tend to shift the bit 28 to the right, but since the orienting fins 34 bear against the right wall portion of the hole 36, the tendency of the bit to shift is overcome and the hole will be drilled straight.

When the upper or additional orienting means 16 is used, it is preferably positioned above the down hole motor 20 which would space it vertically some distance from the orienting means 32,34 at the lower end of the motor. Furthermore, the shoes 18 which project laterally from the orienting means 16 contact the opposite sidewall portion of the hole 36 from that contacted by the orienting fins 34. Obviously, this would cause the upper or additional orienting means 16 to bias the adjacent portion of the drill stem to the right as viewed in FIG. I, while the orienting fins 34 near the bottom of the string will bias that portion of the string to the left. By utilizing two vertically spaced orienting means acting in opposite directions, the angle of slant can be increased over a given footage being drilled.

In FIG. 2 the upper orienting shoes 18 are shown retracted into the sleeve 16. Whether or not the weight of the string is sufficient to impart a bend or bow to the string is immaterial in connection with the showing in FIG. 2. In that FIG., because of the bit 28 which is centered, and the location of the lower orienting ribs 34 to the right, there is a tendency to tilt the string above the lower orienting means 32 toward the left with the upper orienting sleeve 16 eccentric to the vertical axis of the hole. However, the structure of the drill string and the memory of the metal from which it is made are such that the drill string tends to straighten out and center itself in a vertical hole. This tendency, and the location of the orienting sleeves 34 against the right side of the wall of the hole, creates a reverse tilting effect which causes the drill bit 28 to slant slightly to the left as viewed in FIG. 2.

In FIGS. 4 and 6 there is shown a modification wherein there is the lower orienting sleeve 32 and orienting fins 34 as in FIGS. 1 and 3. Sleeve 32 is slidable vertically between a shoulder 33 and the drill bit 35. There is also an upper orienting sleeve 42 having fins 44, the structure of the sleeve and fins 42 and 44 respectively being the same as sleeve 32 and fins 34 with one exception. The upper orienting sleeve 42 is provided with internal splines 46 which complement external splines 48 formed vertically on a sub 50 interconnecting a drill stern section 52 and the upper end of the down hole motor housing 54. This permits the upper orienting sleeve 42 to be indexed rotationally of the drill string and relative to the lower orienting sleeve 32 with its fins 34. As shown in FIG. 4, the fins 34 of the lower orienting structure are directed laterally oppositely to the fins 44 of the upper or additional orienting structure, so that as viewed in that FIG., the lower portion of the drill stem and the drill bit will be biased toward the left to provide for slant drilling or to overcome the tendency to slant in certain formations where truly vertical drilling is desired. The sleeve 42 can be permitted to slide vertically on the splines 48 on sub 50 without altering the indexed position of the sleeve.

In FIG. 4 the drill string between the lower orienting means 32 and the upper orienting means 42 is shown bowed or bent to the left in the same manner as that indicated in F IG. 1, and for the same reasons given in connection with that FIG.

It should be noted in FIG. 6 that the outer vertical edges of the fins can be provided with hardening material 57 to reduce wear on the fins when the string is lowered and raised in the hole. It should also be understood that if desired, the spline arrangement shown in FIG. 6 can also be used on the lower orienting means 32,34 if desired.

In FIG. there is shown another modification wherein there is an upper orienting means 56 which may be the same as the orienting means 16 of FIGS. 1 and 2. This orienting means is preferably located at the upper end of a down hole motor 58. On the lower end of the motor 58 is mounted as by threads 60, a sleeve 62 having helical fins 64 which extend laterally from the sleeve 62 equal distances about the vertical axis of the drill string. The sleeve 62 with its fins 64 comprise a stabilizer to tend to maintain bit 66 centrally of the hole 68. The stabilizer 62,64 per se may be one such as produced by known manufacturers in the oil field supply business. However, in the embodiment of FIG. 5 the stabilizer is utilized in conjunction with orienting means, such as the means 56. With this combination it is possible to drill on a slant since the orienter 56 as viewed in FIG. 5 will bias that portion of the drill string to the right, and since the stabilizer 62,64 is symmetrical, the lower portion of the drill string will be slightly tilted to the left and about the stabilizer 62,64 as a fulcrum. Since the stabilizer 62,64 is located much closer to the bit 66 than the orienting means 56, the effect of the orienting means 56 will be to produce a minimum slant or angle of drilling.

In FIG. 5 since the stabilizer 62,64 extends outwardly from the axis of the drill string equally in all directions, that portion of the drill string will be held concentric to the vertical axis of the hole. Again disregarding any possible bowing or bending due to the weight of the string from the top down, when the upper stabilizer 56 is in the position shown with its shoes 59 projected to the left, the lower end of the string will tilt about the lower stabilizer 62,64 as fulcrum and cause the cutter 66 to slant slightly to the right.

In FIGS. 7 and 8 there is illustrated a modification wherein movable ribs 66 can be used in the sleeve 32 in place of the fixed ribs 34 of FIGS. 1,2 and 4. The ribs are seated in longitudinally extending pistonlike elements 68 provided with suitable packing 70 which fits in a vertical slot 72 in the wall of sleeve 32 to provide a sliding seal between the piston and the sleeve 32. The details of means for shutting off hydraulic pressure to the inside of the sleeve 32 and the rear or working faces of the pistons 68 are not shown since they are well known in the art. This structure is somewhat like that disclosed in US. Pat. NO. 3,298,449 issued Jan. 17, I967 to Bachman et al., on Well Bore Apparatus.

It will be seen that we have provided means for slant drilling (or for maintaining vertical drilling where the formation tends to cause a slant, or for other reasons known in the art, wherein the angle of the lower portion of the drill stem is controlled by guiding means which at least in part is located close to the drill so that it will control the position of the drill rather precisely. The lower orienting means can be used alone or in conjunction with the upper or additional orienting means to give greater control over the angle of slant as well as to increase the amount of slant in a given depth of hole being drilled. It will also be seen that where a precisely controlled minimal angle of slant is desired, an arrangement such as that shown in FIG. 5 can be utilized.

The lower orienting means of FIGS. 1, 2 and 4 can be constructed simply and economically from a sleeve and a pair of fins welded thereto and the bearing housing of a down hole motor can be externally threaded to conveniently receive and retain the orienting sleeve. It has been found that the threaded connection of the sleeve to the lower bearing housing of the down hole motor effectively holds the sleeve thereon and against rotation. However, should the sleeve for some reason become loose and disengaged from the threads of the motor bearing housing, the sleeve can not be lost in the hole because its internal diameter is less than the external diameter of the drill bit.

It should of course be understood that various changes can be made in the form, details, arrangement and proportions of the various parts without departing from the spirit of the invention.

We claim:

1. Drill string orienting apparatus comprising a nonrotating drill string with a down hole motor, a rotating bit sub below i the motor and a bit on the rotating bit sub wherein the improvement comprises: an orienting device on said drill string adjacent said motor in nonrotating relation to the string, said "s orienting device having orienting means thereon projectingv laterally from a side thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means, said orienting means being located below said down hole motor, and additional orienting means having means for locating it on the drill string above the down hole motor, said additional orienting means including means extending radially outwardly in a direction opposite to 7 orienting means relative to said first mentioned orienting means.

3. Drill string orienting apparatus comprising a nonrotating drill string with a down hole motor, a rotating bit sub below the motor and a bit on the rotating bit wherein the improvement comprises: an orienting device on said drill string ad jacent said motor in nonrotating relation to the string, said orienting device having orienting means thereon projecting laterally from a side thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means; said orienting means being located below said down hole motor. and additional orienting means having means for locating it on the drill string above the down hole motor, said additional orienting means including means extending radially outwardly in a direction opposite to that of said first mentioned orienting means, and said drill string having vertical external splines about a portion thereof adjacent said down hole motor, and said additional orienting means including a sleeve having internal splines complementary to those of the drill string and being movable vertically on said drill string into and out of engagement with said vertical external splines to permit rotational indexing of the additional orienting means relative to the first mentioned orienting means.

4. Drill string orienting apparatus for use on a nonrotating drill string with a down hole motor, wherein the improvement comprises: an orienting sleeve on a portion of the drill string adjacent the lower end thereof, said portion of said drill string having vertical external splines thereon, said orienting means including a sleeve having internal splines, and said sleeve being vertically movable on said drill string to bring its splines into and out of engagement with the splines on said drill string portion, whereby said orienting means can be rotationally indexed relative to the drill string.

5. Drill string orienting apparatus comprising a nonrotating drill string having a down hole motor on the lower portion thereof, said down hole motor having a nonrotating lower bearing housing, a bit sub secured to and extending downwardly from said lower bearinghousing, a drill bit connected to said motor through said bit sub for rotation with the motor, wherein the improvement comprises: a sleeve slidable upwardly on and connected to the bottom portion of said lower bearing housing and having orienting means projecting laterally from a side portion thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means. 

1. Drill string orienting apparatus comprising a nonrotating drill string with a down hole motor, a rotating bit sub below the motor and a bit on the rotating bit sub wherein the improvement comprises: an orienting device on said drill string adjacent said motor in nonrotating relation to the string, said orienting device having orienting means thereon projecting laterally from a side thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means, said orienting means being located below said down hole motor, and additional orienting means having means for locating it on the drill string above the down hole motor, said additional orienting means including means extending radially outwardly in a direction opposite to that of said first mentioned orienting means, and said additional orienting means being longitudinally movable within limits relative to the drill string to permit the drill string and drill to move vertically relative thereto.
 2. The structure in claim 1, and said additional orienting means being rotatable relative to said first mentioned orienting means, and means on said drill string and said additional orienting means for rotationally indexing the additional orienting means relative to said first mentioned orienting means.
 3. Drill string orienting apparatus comprising a nonrotating drill string with a down hole motor, a rotating bit sub below the motor and a bit on the rotating bit wherein the improvement comprises: an orienting device on said drill string adjacent said motor in nonrotating relation to the string, said orienting device having orienting means thereon projecting laterally from a side thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means, said orienting means being located below said down hole motor, and additional orienting means having means for locating it on the drill string above the down hole motor, said additional orienting means including means extending radially outwardly in a direction opposite to that of said first mentioned orienting means, and said drill string having vertical external splines about a portion thereof adjacent said down hole motor, and said additional orienting means including a sleeve having internal splines complementary to those of the drill string and being movable vertically on said drill string into and out of engagement with said vertical external splines to permit rotational indexing of the additional orienting means relative to the first mentioned orienting means.
 4. Drill string orienting apparatus for use on a nonrotating drill string with a down hole motor, wherein the improvement comprises: an orienting sleeve on a portion of the drill string adjacent the lower end thereof, said portion of said drill string having vertical external splines thereon, said orienting means including a sleeve having internal spLines, and said sleeve being vertically movable on said drill string to bring its splines into and out of engagement with the splines on said drill string portion, whereby said orienting means can be rotationally indexed relative to the drill string.
 5. Drill string orienting apparatus comprising a nonrotating drill string having a down hole motor on the lower portion thereof, said down hole motor having a nonrotating lower bearing housing, a bit sub secured to and extending downwardly from said lower bearing housing, a drill bit connected to said motor through said bit sub for rotation with the motor, wherein the improvement comprises: a sleeve slidable upwardly on and connected to the bottom portion of said lower bearing housing and having orienting means projecting laterally from a side portion thereof to bear against the hole formation and bias the drill bit in a lateral direction opposite to that of the projecting orienting means. 